August 11, 2016, was supposed to be a historic day for the global effort to eradicate the polio virus. This Thursday would have marked two years since someone on the African continent last contracted the wild-polio virus.
If the continent made it without a case for a third year, the World Health Organization could have certified it as polio-free, and Africa would have joined four other WHO regions—the Americas, Europe, the Western Pacific, and South-East Asia—in eradicating wild polio.
But it is not to be. Nigerian health officials announced on Thursday, the same day they expected to celebrate the anniversary, that two children have been paralyzed by wild polio in the country’s northeastern Borno State.
“It has set us back,” said Isaac Adewole, the Nigerian health minister, according to the Nigerian newspaper Leadership. Borno State will now undergo three rounds of emergency immunizations, he added. Neighboring countries have also been put on alert to look for cases of wild polio.
Matshidiso Moeti, the regional director of WHO in Africa, said he was “deeply saddened” by the news. “The [Nigerian] government has made significant strides to stop this paralyzing disease in recent years. The overriding priority now is to rapidly immunize all children around the affected area and ensure that no other children succumb to this terrible disease.”
“What that means is that the certification will start all over again,” said Haruna Mshelia, the minister of health for Borno State, according to Leadership. “It wasn’t that we were not doing the job. A chunk of the state was out of reach, and we couldn’t reach children there.”
Parts of Borno State are controlled by the terrorist group Boko Haram. One of the public-health campaign’s techniques was to rush in with workers and vaccines as soon as a village was liberated from the group.
Other than Nigeria, only Afghanistan and Pakistan still experience outbreaks of wild polio virus. The two countries have had 19 cases of wild polio so far this year.
Wild polio is not to be confused with vaccine-derived polio, a weaker form of the virus that sometimes emerges when a country’s health system is under considerable stress. Last year, two children in Ukraine contracted this less virulent form of the disease.
Nigeria must now wait at least until the summer of 2019 to receive a polio-free certification. Yet even with Thursday’s setback, the country has made remarkable progress overall: As recently as four years ago, half of all wild polio cases worldwide originated in Nigeria.